- Steelhead and Rainbow Trout
- Oncorhynchus mykiss
- Steelhead and Rainbow Trout Basic Characteristics
- Steelhead and Rainbow Trout Life Cycle
- How to Tell Steelhead and Rainbow Trout Apart
- Rainbow Trout and Steelhead Geographic Distribution
- Behavioral Differences Between Steelhead and Rainbow Trout
- Get Out There
Steelhead and Rainbow Trout:
There are many fish species that call the United States home. Among the fish that populate our waterways few are as sought after as steelhead and rainbow trout. Understanding the differences between these two fish often leaves anglers both confused and intrigued.
In this article we delve into the intricacies of steelhead and rainbow trout. We will explore their physical characteristics, life cycles, migratory patterns, and behavioral differences. Understanding these distinctions isn’t just a matter of curiosity but something that can elevate your fishing game. It’s also quite interesting story.
So, cast your line and join us as we navigate the watery realms in pursuit of what sets Steelhead and Rainbow Trout apart.
Oncorhynchus mykiss:
Big reveal, rainbow trout and steelhead are actually the same species of fish Oncorhynchus mykiss. Yes, you heard that right. Same exact species…
Oncorhynchus mykiss, commonly known as rainbow trout, stands as an icon among the salmonid species. These beautiful fish grace the pristine waters of rivers, streams, and lakes across North America. In fact, many of you have probably caught quite a few of them.
Rainbow trout belong to the family Salmonidae. “Oncorhynchus” referring to the Pacific salmon genus, and “mykiss” which is possibly derived from the German term “forelle,” meaning trout.
Oncorhynchus mykiss exhibits remarkable adaptability. They thrive in a diverse range of aquatic environments from high mountain lakes to rivers and streams, to the ocean. I have yet to go somewhere in the US that does not at a minimum stock these fish.
Anglers and ecologists alike hold a deep appreciation for Oncorhynchus mykiss, as the species not only provides thrilling opportunities for sport fishing and tourism, but also plays a vital role in maintaining the ecological balance of many freshwater ecosystems.
Next let’s dive into some of their basic characteristics.
Steelhead and Rainbow Trout Basic Characteristics:
Steelhead and rainbow trout, boast a set of distinctive characteristics.
Coloration and Physical Description:
Physically, rainbow trout are characterized by a streamlined body covered in small, finely-spaced scales. They typically display a range of colors that vary depending on their environment, age, and reproductive state.
The iconic pink or red stripe that runs along their lateral line is a key identifying feature, lending them their name. Their back is often a deep olive-green, transitioning to a silvery-white belly. In the winter and early spring during the spawn, these colors intensify.
Rainbow trout have adipose fins, small fleshy fins located between the dorsal fin and tail, which are often clipped in hatchery-raised individuals for identification purposes. Their adipose fin is an essential feature distinguishing them from other salmonid species.
Sexual Dimorphism:
Rainbow trout exhibit sexual dimorphism, with males generally displaying more vibrant colors and pronounced physical characteristics than females. For example, larger males often develop a more pronounced jaw, known as a kype.
Feeding Habits:
Rainbow trout are opportunistic feeders, consuming a varied diet that includes insects, crustaceans, small fish, and terrestrial organisms that fall into the water. And fortunately quite a few of my flies.
Beyond their physical traits, rainbow trout showcase a remarkable adaptability, thriving in a spectrum of environments ranging from small mountain streams to large rivers and lakes.
This versatility, coupled with their popularity as a sport fish, has contributed to the widespread distribution of rainbow trout in various freshwater ecosystems, making them a significant and valued species in North American fisheries.
Now let’s look in depth at their life cycle.
Steelhead and Rainbow Trout Life Cycle:
Life cycle is where we begin to get into the true differences between rainbows and their brother’s the steelhead. These fish lead very different lives. It is a fascinating journey, especially for steelhead.
The Spawn:
We begin with the spawning season which typically occurs in the winter and early spring.
Adult rainbow trout migrate to suitable gravel-bottomed streams or riverbeds to lay their eggs. Females create nests, or redds, by using their tails to excavate depressions in the substrate. They then deposit their eggs. Males release milt to fertilize the eggs, initiating the early stages of the life cycle.
Alevins, Fry, and Smolts:
Upon hatching the eggs give rise to alevins, which remain in the gravel and rely on their yolk sacs for nourishment. As they absorb their yolk sacs young trout emerge as fry, venturing into the stream in search of food.
Over time they develop into parr, characterized by distinctive vertical markings along their sides. In the next phase, smolts, rainbow trout begin their migration downstream toward larger bodies of water.
The Path of the Steelhead:
This is where the life cycle of a steelhead diverges.
Some rainbow trout are anadromous. This means they undertake extensive migrations to the ocean. These steelhead smolts undergo physical changes, adapting to the challenges of saltwater environments.
After spending years at sea, steelhead return to their natal streams to spawn, mirroring the freshwater phase of their life cycle.
The ability of Oncorhynchus mykiss to exhibit both freshwater and saltwater phases makes them a really interesting fish. I remember once I learned they were actually the same fish I had to know everything and what a rabbit hole it is.
Let’s look at how to tell the two apart.
Telling Steelhead and Rainbow Trout Apart:
Unfortunately, this is not always easy. Having said that there are markers you can go through to feel pretty confident the fish on the end of your line is indeed a steelhead.
Size:
The biggest difference between the two fish is size. Steelhead are massive fish. The Idaho state catch and release record is 41 inches. Steelhead have been caught weighing over 30 lbs. To put that in perspective catching a 23-inch rainbow trout can be a big highlight for a lot of anglers.
Color:
After spending multiple years in the ocean steelhead are often heavily spotted. Fresh from the ocean steelheads are often have a silvery or brassy color to them.
When you see a steelhead, you can tell there is something different about them. The typical colors and spots you would expect on a rainbow trout seem to be coming from underneath a silver sheen.
On the other side of the coin, your standard rainbow trout showcase vibrant colors, including an array of pinks, reds, and greens.
One thing to note is that steelhead will eventually lose that silver sheen and will look like your typical rainbow trout after living in freshwater for some time.
Steelhead Spawning Run
Steelhead often begin their run in the fall. They spawn in the winter and early spring. That’s also generally steelhead fishing season in most states. If you catch a huge rainbow with a silvery sheen in the months from the fall to the spring then it is highly likely you snagged a steelhead.
Rainbow Trout and Steelhead Geographic Distribution:
Rainbow trout are native to the Pacific slope of North America, ranging from Alaska down to Mexico.
Rainbow trout have been widely introduced and established in various freshwater habitats, including rivers, lakes, and streams. This has extended their distribution well beyond their native range.
Steelhead further extend this distribution as they embark on remarkable journeys between freshwater and saltwater ecosystems.
While their anadromous life phase involves migrating to the ocean, steelhead are known to return to their natal freshwater streams for spawning. This dual nature adds a layer of complexity to their distribution, as steelhead traverse vast distances, navigating coastal waters and inland rivers. They even sometimes return back to the ocean.
Steelhead have been introduced into regions outside their native range, including the Great Lakes in North America and various locations in Europe and Asia. This gives the rainbow trout a truly global presence like their cousin the brown trout.
The adaptability of rainbow trout to a wide range of environmental conditions has made them a popular species for stocking programs, contributing to their distribution in both natural and artificial aquatic settings.
The conservation of native populations, especially in the context of steelhead, requires careful management to preserve the integrity of their migratory corridors and spawning habitats.
Behavioral Differences Between Steelhead and Rainbow Trout:
Rainbow trout spend their entire lives in freshwater environments. The display a more sedentary lifestyle than their ocean going twin, dwelling in rivers, streams, and lakes, where they establish territories and display relatively predictable feeding and spawning behaviors.
On the other hand, as noted above, steelhead undertake extensive migrations between freshwater and saltwater.
The size and feeding behavior of steelhead often differs from rainbow trout. Steelhead, having spent time in the ocean are often significantly larger than their freshwater counterparts, and their feeding habits will include a more diverse diet acquired during their time in saltwater.
Understanding these behavioral distinctions is essential for anglers and fisheries managers as it informs fishing techniques, and habitat preservation efforts.
Get Out There:
In exploring the differences between rainbow trout and steelhead I have outlined the distinctions in their behaviors, life cycles, and habitats.
The rainbow trout in its freshwater home, displays a grounded and territorial demeanor. While the steelhead, it’s anadromous brother, embarks on an epic journey, swimming both fresh and saltwater.
From the vibrant colors that adorn their scales to their epic migrations, these two forms of Oncorhynchus mykiss are fish that should be on every fisherman’s bucket list. Whether you find them in the misty rivers of the Pacific Northwest or the pristine lakes of Idaho, the thrill of the catch is not just a triumph over the elusive steelhead or the gorgeous rainbow trout. It’s a communion with the untamed spirit of these waterways.
In the end, knowing the differences between rainbow trout and steelhead enriches our angling experience.
Tight lines, and may your fishing adventures be filled with vibrant rainbow trout and monster silver steelhead.
– Alpine Angler